Home Space How fast is the Milky Way rotating? How fast is the Milky Way rotating?The galaxy rotates. But how fast and how long does one round trip take? Space 2023-06-28 by Space Navy 0 Comment The galaxy rotates. But how fast and how long does one round trip take? Our galaxy revolves around itself at a speed of 864,000 km per hour. This corresponds to taking our solar system approx. 220 million years to complete one round trip around the center of the Milky Way, but this is also called a galactic year. In the 4.6 billion years that it has existed, the solar system has only orbited the center of the Milky Way 21 times. As a result, the Earth is 21 years old, measured in galactic years. Our solar system is hurtling through the Milky Way at a speed of 864,000 km per hour. Astronomers primarily use radio telescopes to measure the rotation of the galaxy. Celestial bodies emit radio signals, and by studying the signals of certain celestial bodies over a certain number of years, astronomers can measure how certain parts of the galaxy move relative to us. The astronomers can then calculate how fast the orbit rotates around itself.